In-line fuse holder assembly

ABSTRACT

An in-line fuse holder assembly comprising a pair of hollow fuse holder parts having confronting open ends held in abutment by circumferentially spaced axially extending interlocking fingers at the confronting open ends of the fuse holder parts. The fingers have tapering outer ends so the confronting circumferentially facing edges of adjacent fingers of each fuse holder part define a flaring mouth or entryway for the fingers of the other fuse holder part when the fuse holder parts are separated and positioned so the fingers are out of alignment, to permit the open inner ends of the fuse holder parts readily to be brought into abutting relation prior to the interlocking of the fingers thereof. At least one of the fingers of at least one of the fuse holder parts has a narrow shank portion extending rearwardly beyond the end portions of the fingers of the other part when the fuse holder parts are in assembled relation, to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which the latter fuse holder part can be mounted.

United States Patent [1 Schmidt, Jr.

[ lN-LINE FUSE HOLDER ASSEMBLY [75] Inventor: John Schmidt, Jr., Mount Prospect,

[73] Assignee: Littelfuse, 1nc., Des Plaines, 111.

[22] Filed: Feb. 24, 1972 [21] Appl. No.: 228,888

[52] US. Cl. 337/201, 337/207 [51] Int. Cl. ..H01h 85/02 [58] Field of Search 337/166, 186, 190,

[56] References Cited UNITED STATES PATENTS 3,120,593 2/1964 Feenan et al. 337/234 3,243,551 3/1966 Hollins 337/201 X Primary ExaminerBernard A. Gilheany Assistant ExaminerF. E. Bell AltorneySidney Wallenstein et al.

[ 1 Dec. 11, 1973 [57] ABSTRACT An in-line fuse holder assembly comprising a pair of hollow fuse holder parts having confronting open ends held in abutment by circumferentially spaced axially extending interlocking fingers at the confronting open ends of the fuse holder parts. The fingers have taper ing outer ends so the confronting circumferentially facing edges of adjacent fingers of each fuse holder part define a flaring mouth or entryway for the fingers of the other fuse holder part when the fuse holder parts are separated and positioned so the fingers are out of alignment, to permit the open inner ends of the fuse holder parts readily to be brought into abutting relation prior to the interlocking of the fingers thereof. At least one of the fingers of at least one of the fuse holder parts has a narrow shank portion extending rearwardly beyond the end portions of the fingers of the other part when the fuse holder parts are in assembled relation, to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which the latter fuse holder part can be mounted.

12 Claims, 7 Drawing Figures 3! a if 7 7 I IN-LINE FUSE HOLDER ASSEMBLY The present invention relates to an in-line fuse holder assembly which commonly comprises a pair of removably secured together fuse holder parts having open inner ends in confronting relation to define an overall fuse holder space within which is located a fuse generally comprising a transparent cylindrical fuse linkholding body portion closed by terminal-forming end caps. A pair of conductors extend through openings in outer end walls of the fuse holder parts and terminate in conductor terminals which are resiliently urged by spring means against the fuse end caps.

The present invention is an improvement over an inline fuse holder assembly of the type where the fuse holder parts are releasably held together at their confronting open ends against the separating force of the spring means by circumferentially spaced interlocking fingers projecting from the confronting inner ends of the fuse holder parts. Each of the fingers project radially and axially beyond the open end of the fuse holder part from which it extends, and has a hook-shaped end facing in the same direction as the hook-shaped end of the other fingers extending from the same fuse holder part, and in the opposite direction from the hookshaped end of the corresponding finger of the other fuse holder part with which it is to interlock. Generally, there are three such circumferentially spaced fingers on each fuse holder part which, when one fuse holder part is positioned so the fingers thereof are out of alignment with the fingers of the other fuse holder part, permits the fuse holder parts to be brought together so that their confronting open ends are in abutment. The fuse holder parts are then rotated one with respect to the other to bring the oppositely facing hook-shaped ends of the fingers of the fuse holder parts into interlocking relation.

The in-line fuse holder assemblies of the type just described, although satisfactory from 'many viewpoints, have had certain drawbacks, such as the difficulty of orienting the two fuse holder parts and bringing them into abutment where the fingers can be interlocked, and in the somewhat complex manner used heretofore to effect proper alignment of the fuse and conductor terminals within the fuse holder assembly. Additionally, in-line fuse holder assemblies have not been provided with means for mounting the same within an opening in a mounting panel, so that the in-Iine fuse holder assemblies were generally loosely carried by the conductors involved.

One of the objects of the present invention is to provide an in-line fuse holder assembly of the type above described having interlocking hook-shaped fingers for securing together the confronting open ends of a pair of fuse holder parts and, further, wherein the fingers are uniquely designed to facilitate the easier assembly of interlocking of the fingers of the fuse holder parts.

Another object of the invention is to provide an inline fuse holder assembly of the type described above wherein there is provided a simple means for mounting the same in an opening in a mounting panel.

Another object of the invention is to provide an inline fuse holder assembly as described where the fuse holder parts in a simple and inexpensive manner effect the proper alignment of the internal parts of the fuse holder assembly without causing overheating of the fuse due to accumulation of heat within the fuse holder assembly, which would cause undesired blowing of the fuse in the absence of overload current.

The above and other objects of the invention and the features of the invention which satisfy the same will become apparent upon making reference to the specification to follow, the claims and the drawings wherein:

FIG. I is an elevational view of the fuse holder assembly of the present invention as it appears for shipment to the user, and which includes a conductor carrying a selection of coil springs to adapt the fuse holder assembly for use with different fuse sizes;

FIG. 2 is a longitudinal sectional view of the fuse holder assembly of FIG. 1 after the conductor is severed, the coil springs removed therefrom and the smaller coil spring and a relatively large fuse requiring the smaller coil spring is mounted in the fuse holder parts thereshown;

FIG. 3 illustrates a fragmentary side elevational view of the inner open ends of the fuse holder parts of FIGS. 1 and 2 as they are initially brought into abutment prior to being interlocked by the rotation of one fuse holder part relative to the other, to interlock the fingers thereof;

FIG. 4 is a transverse sectional view through the assembled fuse holder assembly in FIG. 2, taken along section line 4-4 thereof;

FIG. 5 is a longitudinal sectional view of the fuse holder assembly of FIG. 1 after severance of the conductor, removal of the springs therefrom, mounting of the larger coil spring and a relatively small fuse in the fuse holder parts thereshown, and the mounting of the fuse holder assembly in a mounting panel;

FIG. 6 is a transverse sectional view through the fuse holder assembly of FIG. 5, taken along section line 6-6 thereof; and

FIG. 7 is an elevational view of a modified form of fuse holder assembly of the invention where the fuse holder parts thereof are made of transparent synthetic plastic material, permitting the fuse to be seen through the walls of the fuse holder parts.

Refer now more particularly to FIGS. 1-4 illustrating an exemplary form of fuse holder assembly 2 including the features of the present invention. As thereshown, the fuse holder assembly includes a pair of fuse holder parts 2a-2a which are most advantageously of identical construction and made of a synthetic plastic molded material. Each fuse holder part has a generally cylindrical body 4 with an end wall 6 at the outer end thereof in which is formed a centered preferably chamfered opening 8 which flares outwardly to the outer surface of end wall 6, to form a guideway for readily guiding the initially loose strands of the bared end of an initially single conductor 10 covered for most of its length by insulation 11. The opposite ends of the conductor 10 are initially pressed through the chamfered openings 8-8 of the fuse holder parts 2a-2a to bring the initially bared ends of these conductors within their respective fuse holder parts 2a-2a. The bared ends of the conductor 10 are then pressed fitted or otherwise secured within the hollow cylindrical shank portions l2a-I2a of conductor terminal members 12-12 each having an outwardly extending head portion 12b at the outermost end of the conductor terminal member. When the fuse holder assembly 2 is arranged for shipment to the ultimate user, as shown in FIG. 1, the single insulated conductor 10 carries a relatively short spring 16 to accommodate a long fuse 17 (FIG. 2) and a relatively large coil spring 16' to accommodate a short fuse 17' (FIG. 5). The insulated conductor is severed by the user so that the desired spring 16 or 16 can be inserted around the insulated conductor within one of the fuse holder parts behind the enlarged head portion 12b of the associated conductor terminal member 12, as shown in FIG. 2.

Each of the fuse holder parts defines a-fuse holder space 13 which opens onto the inner end of the cylindrical fuse holder part body 4 through an opening 14 of the same diameter as the adjacent portion of the fuse holder space 13. Extending between the inner surface of the end wall 6 of each fuse holder part and the axially facing edge 4a thereof are radially inwardly extending axial ribs generally indicated by reference numeral 15. The confronting radially inwardly facing ends of the ribs 15 follow along the contour of an imaginary cylinder centered in the fuse holder space 13 involved. The ribs 15 have an outer stepped portion 150 following the contour of a smaller centered imaginary cylinder and so define a relatively small space for confining the outer end portion of one of the coil springs 16 or 16'. The shank portion 12a of each conductor terminal member 12 is spaced inwardly of the confronting surfaces of the other rib portions 15a to leave a clearance space for one of the coil springs (which may be positioned in either of the fuse holder parts 2a). The outer portion of the coil spring involved is confined and entered by the confronting ends of the outer rib portions 150, while the inner portions of the spring involved seats around and is centered by the outer surface of the hollow shank portion 120 of the associated conductor terminal member 12. The ends of the spring are sandwiched between the enlarged head portion 12b of the conductor terminal member 12 and the fuse holder part end wall 6. In FIG. 2, the small spring 16 is shown urging the conductor terminal member 12 against the terminal-forming end cap 17a of the larger fuse 17. The fuse 17 has the usual transparent cylindrical housing 17b and terminal-forming end caps l7al7a at the ends thereof closing off the open ends of the cylindrical housing 17b within which is contained a fuse link 17c extending between the terminal-forming end caps l7al7a. The spring 16 in the left hand fuse holder part 2a viewed in FIG. 2 urges the fuse 17 against the conductor terminal member 12 in the outer end of the right fuse holder part 2a whose head portion 12b is shown urged against the shoulders 15a at the ends of the outer rib portions 15a.

The fuse 17 fits within the fuse-receiving spaces 13-13 of the fuse holder part 2a- 2a in a manner such that there is a substantial clearance space between the ribs 15 therein and the transparent housing 17 of the fuse. There is a small but finite clearance space provided between the terminal-forming end cap 17a--l7a' of the fuse 17 and the ribs 15, which loosely center the fuse within the fuse holder parts. The provision of the ribs 15 provide substantial spaces between the ribs and limited spaces between the fuse and the ribs for circulation of air, to prevent the build up of heat within the fuse holder assembly which could otherwise cause a false blow-out of the fuse due to accumulated heat.

Means are provided for releasably holding the fuse holder parts 2a-2a together against the force of the coil spring 16 tending to separate the same. This means as illustrated comprise three circumferentially spaced, thin-walled, axially extending fingers 20, 20 and 20 on each fuse holder part which project radially and axially beyond the open ends of the fuse holder part from which they extend. Each of the fingers, as illustrated, has a relatively straight, axially extending narrow shank portion 22 or 22' projecting radially from the outer surface of the cylinderical fuse holder part body 4 involved adjacent the open end thereof, and a hookshaped front end portion 24 positioned for the most part beyond the axially facing edge 4a of the fuse holder part body 4. Each hook-shaped end of each finger of each fuse holder part faces in the same direction as the other fingers of the same fuse holder part and in the opposite direction to the hook-shaped fingers of the other fuse holder part when the fuse holder parts are in assembled position.

The hook-shaped front end portion of each of the fingers taper outwardly thereof, so the confronting circumferentially facing edges of each adjacent pair offingers on each fuse holder part defines a flaring fingerguiding mouth 25 (see FIG. 1) or entryway for guiding a finger of the other fuse holder part when the fuse holder parts are separated and positioned so the fingers are out of alignment, to permit the open inner ends of the fuse holder parts to be guidingly brought into abutting relation prior to the interlocking of the fingers. The width of the hook-shaped front ends of the fingers is thus much less than the size of the mouth or entryway 25 referred to, and somewhat less than the minimum spacing between the outermost lateral edge 27 of each finger and the rear surface 29 of the adjacent finger.

Each of the fingers has an axially outwardly facing surface with an inner relatively recessed section 31 and an outer relatively raised section 33. When the fuse holder parts are rotated into a position with the oppositely facing corresponding hook-shaped fingers in interlocking relationship, the raised section 33 of each finger is positioned within the recessed section 31 of the other fuse holder part. When the confronting edges 4a4a of the fuse holder parts 2a-2a are brought into abutment with the fingers out of alignment as shown in FIG. 3, the raised sections 3333 of the fingers to be interlocked are in overlapping relation, so these fingers must flex to permit the interlocking of the fingers as shown in FIG. I.

The various fingers of each fuse holder part are identical except that the finger 20' has a longer shank portion 22' which terminates in a beveled end portion 22a (FIG. 5) of greater length than the corresponding beveled portions 22a of the fingers 20-20 for reasons now to be explained. The fuse holder assembly 2, unlike those of the prior art, is adapted to be mounted within a circular opening 35 (FIG. 5) within a mounting panel 37. The diameter of the mounting opening 35 is only slightly larger than the diameter of the cylindrical body 4 of the fuse holder part. The mounting opening 35 has a notch 39 therein (FIGS. 5 and 6) into which the end portion of the beveled end 22a of the shank portion 22' of the finger 20' of the fuse holder part involved extends, to prevent rotation of the fuse holder part within the mounting opening 35. When the fuse holder part is inserted to its fullest extent within the opening 35 from the front of the mounting panel 37, the fingers 20-20 and 20 of the latter fuse holder part projects a sufficient distance from the front surface of the mounting panel 37 such that, when the other fuse holder part is positioned in interlocking relationship therewith, the outer ends of the fingers 20-20 and 20' thereof will be adjacent to but slightly spaced from the front surface of the mounting panel 37. The fuse holder part 2a mounted within the panel opening 35 is securely anchored within the opening in any suitable way, such as by the insertion of a split ring 40 or the like around the fuse holder part body 4 behind the mounting panel 37, as shown in FIG. 5, to prevent withdrawal of the fuse holder part from the opening 35 until thd split spring 40 is removed from the body.

Once the fuse holder part 2a has been securely mounted within the panel opening 35, the fingers of the other fuse holder part can be readily interlocked with the fingers of the fuse holder part mounted within the panel with one hand of the operator, who first positions the latter fuse holder part so that the fingers 20, and 20' thereof are at least slightly out of alignment with the fingers of the mounted fuse holder part, and axially moving the latter fuse holder part into position where the edge 4a thereof is in abutment with edge 4a of the former fuse holder part (such movement being aided by the guiding action of the aforementioned flaring entryway or mouth and then rotating the latter fuse holder part clockwise as viewed in the drawing to cause interlocking of the fingers of the fuse holder parts in the manner described previously. (The outer portion of each fuse holder part body 4 is provided with axially extending circumferentially spaced projecting ribs 4b to enable the fuse holder part to be readily grasped and turned with respect to the other fuse holder part when the fuse holder parts are assembled together.)

In one form of the invention shown in FIG. 7, the fuse holder parts 2a-2a' are made of a clear transparent synthetic plastic material so that the fuse is visible through the walls of the fuse holder parts. As illustrated the spacing between the interlocking fingers of the fuse holder parts is such that, after the same has been moved into interlocking relationship, there are substantial clearances left between each of the fingers 20 or 20 of each fuse holder part and the adjacent finger 20 or 20' thereof, so that there is a clear view of the fuse in these spaces so that the center portion of the fuse link 170 of the larger fuse l7 centered in the assembly can be viewed to see if the fuse has been blown, without the need for removing the same from the fuse holder assembly to examine it. In the case of the smaller fuse 17', the center portion of its fuse filament 17c would be visible at a point beyond the fuse holder part fingers, where the fingers do not interfere with a clear view of the fuse filament.

The various forms of the present invention have thus provided an extremely inexpensive, reliable, easy to assembly and mount fuse holder assembly representing a substantial advancement in the art. It should be understood, however, that numerous modifications may be made to the most preferred forms of the invention illustrated, without deviating from the broader aspects of the invention.

The claims:

1. In an in-line fuse holder assembly including a pair of hollow generally cylindrical fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting abutting relation and jointly defining an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said conductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposition direction of the hook-shaped end of the corresponding finger of the other fuse holder part, said raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof, the improvement wherein at least one of said fingers of one of the fuse holder parts has a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point axially be yond the end portions of the fingers of the other fuse holder part to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which said one fuse holder part can be mounted, so the latter fuse holder part remains stationary in said opening while the other fuse holder part can be rotated relative to the latter fuse holder part for disconnecting and re-connecting said fuse holder parts.

2. The in-line fuse holder assembly of claim 1 wherein said fuse holder parts are identical parts made of synthetic plastic insulating material.

3. The in-line fuse holder assembly of claim 1 wherein each of said fuse holder parts has three of said circumferentially spaced axially extending fingers.

4. In combination, a mounting panel with a circular opening having at least one notch in the periphery thereof; and a fuse holder assembly comprising a pair of hollow generally cylindrical fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, one of said fuse holder parts being mounted in said panel opening with said open end spaced forwardly of the front side of said panel, removable anchoring means on said one fuse holder part just behind said panel for anchoring the part in said panel opening and preventing forward removal of said fuse holder part from said opening until it is removed from said fuse holder part, the open ends of the other fuse holder part being in confronting abutting relation to and defining with said one fuse holder part an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts from the opposite sides of said panel and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said conductor and said terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending resilient flexible fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, the fingers of the fuse holder part mounted in said panel opening preventing rearward movement thereof through said panel opening, the fingers of the latter fuse holder part having a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point adjacent to the mounting panel, and one of said finger shank portions extending further to project into said notch in said panel opening to prevent rotation of the latter fuse holder part, said fingers of each fuse holder part having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped front end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook-shaped end of the corresponding finger of the other fuse holder part, the raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of the fuse holder part on the front side of said mounting panel relative to the fuse holder part anchored in said panel opening, to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder part effects the complete separation of the fuse holder parts.

5. In an in-line fuse holder assembly including a pair of hollow fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting abutting relation and jointly defining an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said .conductor terminals and said fuse positioned between said conductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook'shaped end of the corresponding finger of the other fuse holder part, said raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof the improvement wherein the outer ends of said fingers taper outwardly thereof so the confronting circumferentially having edges of each adjacent pair of fingers on each fuse holder part defines a flaring finger-guiding entryway for a finger of the other fuse holder part when the fuse holder parts are separated and positioned so the fingers thereof are out of alignment, to permit the open inner ends of the fuse holder parts to be guidingly brought into abutting relative prior to the interlocking of the fingers thereof.

6. The in-line fuse holder assembly of claim 5 wherein said fuse holder parts are identical parts made of synthetic plastic insulating material.

7. The in-line fuse holder assembly of claim 5 wherein each of said fuse holder parts has three of said circumferentially spaced axially extending fingers.

8. The in-line fuse holder assembly of claim 5 wherein at least one of said fingers of one of the fuse holder parts has a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point axially rearward of the end portions of the fingers of the other fuse holder part, to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which said one fuse holder part can be mounted, so the latter fuse holder part remains stationary in said opening while the other fuse holder part can be rotated relative to the latter fuse holder part for disconnecting and re-connectingsaid fuse holder parts.

9. In an in-line fuse holder assembly comprising a pair of hollow fuse holder parts each having at the inner end thereof an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting relation to jointly define an overall fuse holder space for holding an overload current fuse having spaced conductive end terminals on a fuse body containing a fuse material connected between said terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at. the ends thereof adapted to make conductive engagement with the terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said con ductor terminals and said fuse positioned between said conductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts wherein the fuse can be inserted in or removed from said fuse holder parts by separating said fuse holder parts, the improvement wherein said fuse holder parts have circumferentially spaced generally axially extending ribs within said fuse-holding space therein for loosely centering said fuse therein and to provide space for air circulation around the fuse to prevent heat accumulation which would melt the fuse link in the absence of an overload current and fuse terminal contacting means for holding the portion of said fuse body between said end terminals in spaced relation to said ribs.

10. The in-line fuse holder assembly of claim 9 combined with said overload fuse and said fuse terminal contact means are terminals secured to the end of said contactors which terminals receive the end terminals of the fuse.

11. The in-line fuse holder assembly of claim 9 wherein the ribs at the outer end of each of the fuse holder parts have stepped outermost portions where the ribs are spaced relatively closely together to define a conductor terminal and spring-centering space, each of said conductor terminals comprising a terminal member having a relatively small shank portion secured to the associated conductor and spaced from the confronting surfaces of the associated fuse holder p'art ribs and an outwardly extending fuse centering and engaging head portion of larger size than the spacing between the confronting surfaces of said outermost portions of the ribs, and said spring means being a coil spring centered in the space between the shank portion of one of the conductor terminals and the confronting surfaces of the outermost portions of said ribs, the latter end of the latter holder part having an end wall against which one end of said coil spring bears, the other end of said coil spring engaging the head portion of the associated conductor terminal for urging the same against the adjacent terminal of the fuse in the fuse holder assembly.

12. An in-line fuse holder assembly comprising: a pair of hollow fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting relation to jointly define an overall fuse holder space for holding a fuse having spaced conductive terminals on the ends of a transparent housing through which a meltable fuse link connecting the fuse terminals is visible, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals together, circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hookshaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook-shaped end of the corresponding finger of the other fuse holder part, said raised and recessed sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof, said fuse holder parts being made of a clear transparent insulating material so said fuse link is visible through the fuse holder parts and there being spaces between the interlocking fingers of the fuse holder parts to present a view of the fuse link of the fuse undistorted by the interlocking fingers. 

1. In an in-line fuse holder assembly including a pair of hollow generally cylindrical fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting abutting relation and jointly defining an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said cOnductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposition direction of the hook-shaped end of the corresponding finger of the other fuse holder part, said raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof, the improvement wherein at least one of said fingers of one of the fuse holder parts has a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point axially beyond the end portions of the fingers of the other fuse holder part to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which said one fuse holder part can be mounted, so the latter fuse holder part remains stationary in said opening while the other fuse holder part can be rotated relative to the latter fuse holder part for disconnecting and re-connecting said fuse holder parts.
 2. The in-line fuse holder assembly of claim 1 wherein said fuse holder parts are identical parts made of synthetic plastic insulating material.
 3. The in-line fuse holder assembly of claim 1 wherein each of said fuse holder parts has three of said circumferentially spaced axially extending fingers.
 4. In combination, a mounting panel with a circular opening having at least one notch in the periphery thereof; and a fuse holder assembly comprising a pair of hollow generally cylindrical fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, one of said fuse holder parts being mounted in said panel opening with said open end spaced forwardly of the front side of said panel, removable anchoring means on said one fuse holder part just behind said panel for anchoring the part in said panel opening and preventing forward removal of said fuse holder part from said opening until it is removed from said fuse holder part, the open ends of the other fuse holder part being in confronting abutting relation to and defining with said one fuse holder part an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts from the opposite sides of said panel and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said conductor and said terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending resilient flexible fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, the fingers of the fuse holder part mounted in said panel opening preventing rearward movement thereof through said panel opening, tHe fingers of the latter fuse holder part having a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point adjacent to the mounting panel, and one of said finger shank portions extending further to project into said notch in said panel opening to prevent rotation of the latter fuse holder part, said fingers of each fuse holder part having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped front end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook-shaped end of the corresponding finger of the other fuse holder part, the raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of the fuse holder part on the front side of said mounting panel relative to the fuse holder part anchored in said panel opening, to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder part effects the complete separation of the fuse holder parts.
 5. In an in-line fuse holder assembly including a pair of hollow fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting abutting relation and jointly defining an overall fuse holder space for holding a fuse having spaced conductive end terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said conductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts together comprising circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook-shaped end of the corresponding finger of the other fuse holder part, said raised and recessed surface sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof , the improvement wherein the outer ends of said fingers taper outwardly thereof so the confronting circumferentially having edges of each adjacent pair of fingers on each fuse holder part defines a flaring finger-guiding entryway for a finger of the other fuse holder part when the fuse holder parts are separated and positioned so the fingers thereof are out of alignment, to permit the open inner ends of the fuse holder parts to be guidingly brought into abutting relative prior to the interlocking of the fingers thereof.
 6. The in-line fuse holder assembly of claim 5 wherein said fuse holder parts are identical parts made of synthetic plastic insulatiNg material.
 7. The in-line fuse holder assembly of claim 5 wherein each of said fuse holder parts has three of said circumferentially spaced axially extending fingers.
 8. The in-line fuse holder assembly of claim 5 wherein at least one of said fingers of one of the fuse holder parts has a relatively narrow shank portion extending axially inwardly of the open end of the latter fuse holder part to a point axially rearward of the end portions of the fingers of the other fuse holder part, to form an anchoring rib insertable into a notch in a circular mounting opening of a panel in which said one fuse holder part can be mounted, so the latter fuse holder part remains stationary in said opening while the other fuse holder part can be rotated relative to the latter fuse holder part for disconnecting and re-connecting said fuse holder parts.
 9. In an in-line fuse holder assembly comprising a pair of hollow fuse holder parts each having at the inner end thereof an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting relation to jointly define an overall fuse holder space for holding an overload current fuse having spaced conductive end terminals on a fuse body containing a fuse material connected between said terminals, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals and said fuse positioned between said conductor terminals together, and means for removably securing together the confronting ends of said fuse holder parts wherein the fuse can be inserted in or removed from said fuse holder parts by separating said fuse holder parts, the improvement wherein said fuse holder parts have circumferentially spaced generally axially extending ribs within said fuse-holding space therein for loosely centering said fuse therein and to provide space for air circulation around the fuse to prevent heat accumulation which would melt the fuse link in the absence of an overload current and fuse terminal contacting means for holding the portion of said fuse body between said end terminals in spaced relation to said ribs.
 10. The in-line fuse holder assembly of claim 9 combined with said overload fuse and said fuse terminal contact means are terminals secured to the end of said contactors which terminals receive the end terminals of the fuse.
 11. The in-line fuse holder assembly of claim 9 wherein the ribs at the outer end of each of the fuse holder parts have stepped outermost portions where the ribs are spaced relatively closely together to define a conductor terminal and spring-centering space, each of said conductor terminals comprising a terminal member having a relatively small shank portion secured to the associated conductor and spaced from the confronting surfaces of the associated fuse holder part ribs and an outwardly extending fuse centering and engaging head portion of larger size than the spacing between the confronting surfaces of said outermost portions of the ribs, and said spring means being a coil spring centered in the space between the shank portion of one of the conductor terminals and the confronting surfaces of the outermost portions of said ribs, the latter end of the latter holder part having an end wall against which one end of said coil spring bears, the other end of said coil spring engaging the head portion of the associated conductor terminal for urging the same against the adjacent terminal of the fuse in the fuse holder assembly.
 12. An in-line fuse holder assembly comprising: a pair of hollow fuse holder parts each having at one end an opening forming an entryway into a fuse-holding space in the fuse holder part, the open ends of said fuse holder part being in confronting relation to jointly define an overall fuse holder sPace for holding a fuse having spaced conductive terminals on the ends of a transparent housing through which a meltable fuse link connecting the fuse terminals is visible, a pair of conductors extending into the outermost ends of said fuse holder parts and having terminals at the ends thereof adapted to make conductive engagement with the end terminals of said fuse, spring means in at least one of said fuse holder parts for resiliently urging said conductor terminals together, circumferentially spaced, axially extending fingers on the confronting open ends of each of said fuse holder parts which fingers project radially and axially beyond the open end of the fuse holder part from which they extend, each of said fingers having a resilient and flexible hook-shaped end formed by circumferentially extending portions having an axially outwardly facing surface with an inner relatively recessed section and an outer relatively raised section, each hook-shaped end of each finger of each fuse holder part facing in the same direction as the hook-shaped end of each finger of the fuse holder part from which it extends and facing in the opposite direction of the hook-shaped end of the corresponding finger of the other fuse holder part, said raised and recessed sections of the corresponding fingers of the fuse holder parts being in interlocking relation and being releasable by rotation of one fuse holder part relative to the other to release the interlocked fingers and to bring them out of alignment where relative outward axial movement of the fuse holder parts effects the complete separation thereof, said fuse holder parts being made of a clear transparent insulating material so said fuse link is visible through the fuse holder parts and there being spaces between the interlocking fingers of the fuse holder parts to present a view of the fuse link of the fuse undistorted by the interlocking fingers. 